test: 🚑 add test to catch recursion when persistent grades disabled

lms/djangoapps/certificates/generation_handler.py

@@ -53,7 +53,7 @@ def generate_allowlist_certificate_task(user, course_key, generation_mode=None,
     Create a task to generate an allowlist certificate for this user in this course run.
     """
     enrollment_mode = _get_enrollment_mode(user, course_key)
-    course_grade = _get_course_grade(user, course_key)
+    course_grade = _get_course_grade(user, course_key, send_grade_signals=False)
     if _can_generate_allowlist_certificate(user, course_key, enrollment_mode):
         return _generate_certificate_task(user=user, course_key=course_key, enrollment_mode=enrollment_mode,
                                           course_grade=course_grade, generation_mode=generation_mode,
@@ -377,9 +377,12 @@ def _get_grade_value(course_grade):
     return ''
 
 
-def _get_course_grade(user, course_key, send_grade_signals=False):
+def _get_course_grade(user, course_key, send_grade_signals=True):
     """
     Get the user's course grade in this course run. Note that this may be None.
+
+    Use send_grade_signals=False to avoid firing the course grade signals recursively.
+    See details in lms/djangoapps/grades/course_grade_factory.py _update method.
     """
     return CourseGradeFactory().read(user, course_key=course_key, send_grade_signals=send_grade_signals)
 

lms/djangoapps/grades/tests/test_course_grade_factory.py

@@ -2,16 +2,19 @@
 Tests for the CourseGradeFactory class.
 """
 import itertools
-from unittest.mock import patch
+from unittest.mock import patch, Mock
 
 import ddt
 from django.conf import settings
 from edx_toggles.toggles.testutils import override_waffle_switch
+import pytest
 
 from common.djangoapps.student.tests.factories import UserFactory
+from lms.djangoapps.certificates.config import AUTO_CERTIFICATE_GENERATION
 from lms.djangoapps.courseware.access import has_access
 from lms.djangoapps.grades.config.tests.utils import persistent_grades_feature_flags
 from openedx.core.djangoapps.content.block_structure.factory import BlockStructureFactory
+from openedx.core.djangoapps.signals.signals import COURSE_GRADE_NOW_PASSED
 from xmodule.modulestore.tests.django_utils import SharedModuleStoreTestCase  # lint-amnesty, pylint: disable=wrong-import-order
 from xmodule.modulestore.tests.factories import CourseFactory  # lint-amnesty, pylint: disable=wrong-import-order
 
@@ -73,6 +76,35 @@ class TestCourseGradeFactory(GradeTestBase):
                 grade_factory.read(self.request.user, self.course)
         assert mock_read_grade.called == (feature_flag and course_setting)
 
+    @patch.dict(settings.FEATURES, {'PERSISTENT_GRADES_ENABLED_FOR_ALL_TESTS': False})
+    def test_no_recursion_without_persistent_grades(self):
+        """
+        Course grade signals should not be fired recursively when persistent grades are disabled.
+        """
+        self.mock_process_signal = Mock()  # pylint: disable=attribute-defined-outside-init
+
+        def handler(**kwargs):
+            """
+            Mock signal receiver.
+            """
+            self.mock_process_signal()
+
+        with persistent_grades_feature_flags(
+            global_flag=False,
+            enabled_for_all_courses=False,
+            course_id=self.course.id,
+            enabled_for_course=False
+        ):
+            with override_waffle_switch(AUTO_CERTIFICATE_GENERATION, active=True), mock_get_score(2, 2):
+                COURSE_GRADE_NOW_PASSED.connect(handler)
+                try:
+                    CourseGradeFactory().update(self.request.user, self.course)
+                except RecursionError:
+                    pytest.fail("The COURSE_GRADE_NOW_PASSED signal fired recursively.")
+
+        self.mock_process_signal.assert_called_once()
+        COURSE_GRADE_NOW_PASSED.disconnect(handler)
+
     def test_read_and_update(self):
         grade_factory = CourseGradeFactory()